change of surname for minnor child

I Isabella Elizabeth Kunz apply to change my child's surname at home affairs on the 11-07-2015, (Dirk Jacobus Christoffel du Plessis must change to Kunz ID ***) They told me it will take between 3-6 months, but i'm still straggle, In November they told me the documents is lost and I must sent new documents again so we email and fax it to them , December I must sent again, 4 January 2016 I sent a new application with all the documents, but they let me know it wasn't stamp, so on the 9 January again we sent all the documents. We email all the documents, fax and post all of it. They received it at amendment on the 19 February 2016. On the 11 March 2016 the documents is lost again, on 14 March 2016 they have the documents but there some of the documents is lost. 14 March 2016 Cullinan email again everything, but on the 15 March 2016 they still not received the documents. What must I do, I need to solved this, I did sent emails to the DG on the 20 January 2016 but no one even answer my emails.